Sewing machine support



June.29, 1943. l A LIABAsl-RE 2,322,946

SEWING MACHINE SUPPORT Filed May 2, 1942 HLBERTL/HBHSTRE BY @mM-KM .lHTTORNEY Patented June 29, 1943 UNITED STATES PATENT y OFFICE f2,322,946

SEWING MACHINE SUPPORT Albert Liabastre, Great Neck, N. Y.

Application May 2, 1942, Serial No. 441,560

2 Claims.

This invention is a support for electrically operated sewing machinessuch as are commonly employed by professional operators in productionplants. Sewing machines of this type are operated at high speed. Themoving parts thereof are heavier than in the common household machineand such machines are commonly mounted on tables which are supportedfrom the iioor by stamped or cast metal frames with legs. When a 'numberof these machines are in operation, heavy vibration of the moving partsis transmitted through the table to the floor and if these machines aresupported directly on the floor, the iioor and the walls of the buildingunite to form a sounding board so that persons on the iloor below findthe noise unbearable and in some cases, particularly in frame buildings,it is impossible to keep tenants on the lower floors.

Numerous attempts have been made to over- 'come these diiiiculties. Themost satisfactory, from the noise aspect, has been to interpose feltpads between the machine table legs and the floor, This practice hasmaterially assisted in damping of vibration to the floor, but thispractice has not met with favor for the unforeseen reason that the feltpads are found, in practice, to be ideal breeding places for roaches andother forms of vermin. It is not uncommon for a work room equipped withfelt machine pads to be overrun with roaches. These are obnoxious,physically damage the product of the shop, and get int-o the goods whichare shipped out and result in lost or dissatisfied customers.

Notwithstanding a long felt Want for some satisfactory solution to thesetroublesome problems, universal in the sewing industry, no satisfactorysolution has been suggested until the advent of the present invention.One factor of the problem consists in the wide diversity in the weightsthat must be supported for in some cases weights as low as sixty poundsare transmitted through the legs of the machine ta-ble while in othercases the weights will run as high as 500 pounds. Pads of laminated feltare Well able to withstand these widely different Weights, and at thesame time cushion the vibration. However, when it was attempted tosubstitute for the felt some other resilient element, such, for example,as springs or rubber, great diiculty was experi enced in providingeither springs or rubber which would satisfactorily operate under thesewidely different weight conditions. For example, rubber which wassufiiciently resilient or springy to carry sixty pounds weight would becrushed so as not to satisfactorily carry out its functions when sub#jected to pressures of ve hundred pounds. Attempts were made to enclosesoft rubber within casings. However, if the casing completely enclosedthe rubber the latter lost the necessary resiliency while if the casingdid not completely enclose the rubber, the rubber squeezed from the openpart of the casing in such manner that the casing cut the protrudingportion of the rubber which, after a short time, lost its usefulness bypermitting portions of the casing todirectly contact with the floor. Y

After much experimentation and prolonged tests I at last succeeded inproducing a satisfactory solution of the difficulties stated, `byemploying a relatively soft rubber, such as sponge rubber, and byconfining only a portion of the mass of such rubberwithin a metalcasing, so constituted that those portions of the rubber which might beexpanded to the exterior of the casing under the load of heavy weightswould be adequately protected against damage by the casing. Thisstructure constitutes the present invention.

In the support of this invention I provide a block of rubber which is,in practice, a thick fiat rectangular slab somewhat greater in lengththan in width. This slab is adapted to rest flat upon the oor. On thetop of the rubber slaby is a metal plateprovided around its four sideswith an integral depending skirt of a depth approximately one-half ofthe thickness of the slab. The upper portion of this skirt isperpendicular to the plate and closely conforms to and embraces thecontiguous edges of the slab. The lower margin of the skirt, however, isared outwardly on a curve substantially tangent to the upper portion ofthe skirt and terminates in a blunt or rounded free edge, so that nomatter how much weight is a'pplied to the plate or how much the exposedportion of the rubber slab is squeezed laterally beyond the confines ofthe skirt, there will be no sharp confining edges to cut the -rubber ordisintegrate the same.

Thisstructure has proven to be a complete solution ofthe problemandpermits of the satis` factory support of machines and tables rangingwithin the weights indicated with very marked eiiciency in the dampingof vibration. There is no necessity of securing the machine or rubberdirectly to the floor for, in practice, it is' found that` the rubbersla'b gripsthe floor so firmly and with such Afriction that, when suchmachine is bolted or otherwise secured to the plate, the

machine will not shift on theiioor.

Features' of the invention, other than those adverted to, will beapparent from .thehereinafter detailed description and claims, when readin conjunction with the accompanying drawing.

The accompanying drawing illustrates one practical embodiment `of theinvention, but the construction therein shown is to be understood asillustrative, only, and not as defining the limits of the invention.

Figure 1 is a perspective view of the lower end portion of a sewingmachine table leg resting upon a support embodying the presentinvention.

Figure 2 is a central vertical longitudinal Section of the installationshown in Fig. 1 with a portion of the leg and the binding bolts inelevation.

Figure 3 is a diagrammatic fragmental vertical section of the structureof the present invention showing the manner in which the rubber slabreacts under the imposition of' various weights thereon.

Figure 3a is a view similar to Figure '3, but showing the behavior ofthe rubber slab with a skirt which is not ared as hereinbeforedescribed.r

Referring to the drawing, I designates a slab of rubber which is ofrelatively soft resilient character and may conveniently be spongerubber. In practice this slab ris formed with'parallel upper and lowersurfaces and straight sides. It is in` the form ofa solid block, exceptthat it is provided with recesses 2 in its upper face to receive theheads of binding bolts 4 the function of which will be hereinafterexplained. The lower face of the rubber slab is adapted to rest upon thefloor and frictionally engage therewith.

Overlying the upper face of the slab and substantially coextensivetherewith is a metal plate 5 lwhich may be -conveniently made in theform of a metal stamping provided around its outer periphery with anintegral depending skirt 6 closely embracing'the rubber` slab I andextending downwardly for about one-half the height of the slab. The legI of the sewing machine table'isy of channel form and is provided at itsbottom with one or more laterally extending anchorage ears 8 each ofwhich is provided with a reinforcing boss 9 having therein a slot ID fora binding bolt 4.

The ears 8 are adapted to seat upon the upper surface of the plate 5which is perforated to register with 'the slots I0 -of said ears and thebinding bolts 4 are passed through these alined openings with the headsof the bolts occupying the recesses 2 inthe rubber slab. The nutsl ofthe bolts seat on the bosses 9 and serve to rmly bind the leg of themachine to the plate 5 with the leg disposed substantially centrally ofthe plate, so as to impose the weight of the machine uniformly over theplate in such manner that f there is no tendency of the plate to tilt.

The manner in which the present invention serves to carry out itsfunction is exhibited diagrammatically in Figs. 3 and 3a, the former ofwhich shows a skirt ared at its lower portion, while the latter of whichshows a straight yskirt without the are. In these figures, the full lineposition of the plate and skirt indicated at A is that wherein the partsare not subjected to any load. The position indicated in dotted lines atBl shows the parts depressed under a load of say 60 pounds, while thedot and dash line position indicated at C is that which might correspondwith a load of say 500pounds.

From the neutral position A the plate and its sk-i-rt are increasinglydepressed as the load is increased and as the load is increased therubber slab is placed under greater compression. That portion of therubber which is housed within the straight portion of the skirt cannotexpand laterally, but the unembraced portion of the slab below the loweredge of the skirt is free to expand and does in practice expand to agreater or lesser extent depending upon the load. Note rst Figure 3a.When no load is present the entire lateral edge of the slab issubstantially perpendicular and straight except that it may be slightlycompressed where it fits into the skirt. In the position B in Fig. 3a,that portion of the rubber below the edge of the skirt has eX- pandedinto the dotted line position indicated at II sov as to form a bulge,the upper edge of which is dened by the lower relatively sharp edge ofthe skirt, the inner periphery of which tends to bite into the top ofthis bulge as indicated at I2. If `the weight is increased to the valueindicated at C in Fig. 3, the bulge of the rubber, beyond the confinesof the skirt will be greatly increased and as this bulge increases thelower edge of the skirt will bite into it, not only at the innerperiphery I4, but also at the outer periphery I5 for the bulge beyondthe thickness of-the wall, indicated at t, willeXpand in an upwarddirection because it is freed from -directly imposed downward pressure.That portion of the rubber lying beneath the plate will be subjected toa downward compression coextensive with the plate, that portion beneaththe edge of the skirt and within the area t will also be subjected to adownward compression, while that portion of the bulge I3 beyond theperiphery of the skirt will expand upwardly. Thus the relatively thinedge of the plate will bite into this bulge, particularly at the edgesI4 and I5 and tend to cut and disrupt the same. When it is borne inmindthat these parts are not in a condition of rest, but are ratherunder continuous vibration, it will be apparent that the lower edge ofthe skirt of Fig. 3a will have a cutting or sawing action upon therubber which in a relatively short time will do serious damage thereto.In time the relatively sharp thin edge of the skirt may cut through thebulging portion of the rubber so as to actually contact with the oor andtransmit directly thereto the vibration which it is the intended purposeof the device to eliminate.

In contradistinction to the arrangement shown in Fig. 3a, the structureof Fig. 3 is illustrative ofthe present invention. Here the lowerportion of the skirt is flared outwardly as shown at I6, so as topresent a smooth and unbroken curvilinear inner and under surfaceforming a continuation or merging into the sheer surface of thesuperimposed portion of the skirt. lli/hen a load indicated at B isimposed upon the rubber in Fig. `3, the resulting bulge VI merges intothe curvilinear portion of the skirt in a substantially tangentialmanner. There is no sharp edge to cut into the bulge as in Fig. 3a norany tendency of the skirt t-o harm the rubber. Moreover, when aload-indicated at C is imposed upon the structure, the rubber may bulgeto the extent-indicated at I8, but this bulge is minimized by the factthat the ared portion of the skirt bears directly down on the bulge overan area designated t-I, which is equal tothe thickness of the' Skirtplus the lateral extension of the vflare thereof, 'so that the flare ofthev skirt actually becomes a load carrying member over the areat-t, incontradistinction to the lesser area t of Fig. 3a. Throughout the areat-lthe entire bulge bears against the smooth uninterrupted curvilinearsurface of the flare and there is no cutting action whatsoever, such asis shown in Fig. 3a. The result of the flared portion therefore is toeliminate al1 cutting action, and to increase the bearing surface on therubber whereby it is rendered better able to withstand heavy loadswithout damage and with efficiency in the performance of its intendedfunctions.

By utilizingthis construction I nd it possible to use much softer rubberand thus obtain a much superior cushioning action than could possibly beeven hoped for'iwith such an arrangement shown in Fig. 3a.

In the accompanying drawing I have set forth the preferred'form of thepresent invention but the invention isjto be understood as fullycommensurate with the appended claims.

Having thusfffully described the invention, what I claim as new anddesire to secure by Letters Patent is: 1

1. A support for a sewing machine table comprising a rigid metal platesecured to and underlying the lower end of the leg of the table with theleg of the table arranged centrally ofthe plate, said plate having atits outer margin a depending skirt the upper portion of which issubstantially normal to the plate and the lower Afree edge portion ofwhich skirt is outwardly plate to bolt the plate to the lip, said platebeing provided at its outer periphery with a depending skirt the upperportion of which is substantially normal to the plate and the lowerportion of which is flared outwardly on an unbroken curve, and a slab ofrelatively soft rubber positioned wholly below the plate with the upperportion of the slab embraced by the skirt and the lower portion of theslab being unconfined to permit lateral expansion thereof.

ALBERT LIA'BASTRE.

